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HAZARDOUZ HYDROLOGICAL PHENOMENA IN ARAL SEE BASIN UNDER THE CONDITIONS OF FUTURE CLIMATE CHANGE

Congress: 2008
Author(s): Natalya Agaltseva, Tatyana Spectorman
Research Hydrometeorological Institute (NIGMI), Uzhydromet K.Makhsumova 72, Tashkent, Republic of Uzbekistan Tel. 998 71 1341356 E- mail:hydrology@uzsci.net

Keyword(s): climate change, water resources, natural desasters
AbstractWater resources of the Aral Sea basin are limited and concentrated into the main transboundary Amudarya and Syrdaya rivers. They are formed in the mountains due to melting seasonal snow cover and glaciers. Glaciers of the mountain part of Central Asia are the most important source and long-term reserve of clear and fresh water. However ice resources are not stable. Intensive precipitation and low temperatures create favorable conditions for runoff formation. Climate warming has negative impact to the snow accumulation conditions in mountains and intensifies degradation of glaciation. The recent problem related to expected climate changes is to be considered in the light of the assessment of climate changes impact to the water resources .Assessment and analysis of water resources vulnerability of the main transboundary rivers in respect to climate changes have a great importance under current conditions and this importance will go up year by year. The activities addressed to prevention and mitigation the consequences of natural disasters related to climate and water, mudflow and flood activity as well as hydrological drought has the highest priority for basin of Amudarya river. Study of climate dynamics being based on the series of instrumental observations has shown that recent various climate system components have been changing in the region. A clear tendency to warming is observed over the territory of region with 2004 as the warmest year for the all period of instrumental observations. Data of observations in the mountain river basins and calculations made on the base of mathematical models show sustainable glacier degradation and decrease of snow supplies. The assessment of water resources in the future are determined by the particular models and scenarios. New climate scenarios based on modern equilibrium general atmosphere circulation models and constructed in accordance with A2 (unfavorable) and B2 (moderate) scenarios for 2030 and 2050 have been used. Special attention is paid to study and forecasting extreme drought events as extremely hazardous phenomenon and identification of adaptation ways was completed. All these procedures were made on the mathematical models basis. The researches data show that climate changes are followed by the increase of the extreme weather events, heavy precipitation, and mudflows etc. that cause considerable damage .Precipitation will mostly fall as rains (most of the global climate models scenarios shows an increase in seasonal amount of precipitation) due to strengthening of climate aridity that results in rainfall floods and strengthening mudflow activities. The maximum discharges of mudflows with rain genesis will increase up 20-25% by 2030. Rise in air temperature in a glacier adjacent area will increase probability of overflowing lake hollows and emerging new lakes in a glacier recession area; a danger will increase of breaking dams of these lakes in the glacier recession area and emerging mudflow flood in high mountains. Researches on Amudarya river basin were worked up under support of the INCO516761 «Interstate Water Resource Rick Management: Towards A Sustainable Future for the Aral Basin:» project.
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